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关键词： Fasteners   Computer science   Training data   Propagation losses   Training   Task analysis   Smoothing methods   Negative sampling   three-region principle   embedding mergence   graph-based recommendation  

摘要： Graph - based recommendation systems are blossoming recently, which models user-item interactions as a user-item graph and utilizes graph neural networks (GNNs) to learn the embeddings for users and items. A fundamental challenge of graph-based recommendation is that there only exists observed positive user-item pairs in the user-item graph. Negative sampling is a vital technique to solve the one-class problem and is widely used in many recommendation methods. However, the previous works only focus on the design of negative sampling distribution but ignore the sampled region for negative sampling. In this work, we propose the Three-Region Principle to guide negative sampling, which suggests that we should negatively sample more items at an intermediate region and less adjacent and distant items. In light of this principle, we present the RecNS method, which is a general negative sampling method designed with two sampling strategies: positive-assisted sampling and exposure-augmented sampling. Instead of sampling existing negative items from graph data, we merge these two strategies in embedding space to generate negative item embeddings. Extensive experiments demonstrate that RecNS method significantly outperforms all negative sampling baselines, e.g., 10.47% for PinSage, 6.02% for NGCF, and 8.20% for LightGCN in terms of Recall@20 on the Alibaba dataset.

关键词： 新工科   计算机科学与技术专业   教学改革  

摘要： 在新工科背景下,为了使地方高校尽快适应科技现代化发展,大力发展计算机课程教育改革是十分必要的。目前,地方高校工科教育仍存在一些问题,要解决这些问题就要从教学的课程安排、师资力量、校企合作、改革评价等方面出发,探索教学改革方案,为地方高校的计算机课程改革提供方向。

关键词： 黑核桃   组织培养   褐化   污染   幼嫩茎段  

摘要： 【目的】筛选出消毒的最佳时间和抗褐化剂的最适浓度,研究外植体细胞结构在褐化过程中的变化,为黑核桃的组培研究和工厂化育苗提供理论基础。【方法】采用不同时长对黑核桃叶片和茎段进行消毒处理,观察其对污染率、褐化率的影响;以AC、PVP、VC 3种抗褐化剂进行正交试验,研究其对黑核桃茎段褐化率和萌发率的影响;观察褐化外植体徒手切片。【结果】(1)叶片以0.1%HgCl_(2)消毒5 min,污染率和褐化率最低;(2)茎段以二次消毒法,0.1%HgCl_(2)加吐温80消毒5 min,污染率和褐化率最低;(3)以AC 2 g/L、PVP 110 mg/L、VC 100 mg/L处理的褐化率最低;以AC 1 g/L、PVP 70 mg/L、VC 50 mg/L处理的萌发率最高。【结论】叶片以0.1%HgCl_(2)消毒5min为最佳消毒时间;茎段以二次消毒法,0.1%HgCl_(2)加吐温80消毒5 min为最佳消毒时间;最适的抗褐化剂浓度配比为AC1g/L、PVP 110 mg/L、VC100 mg/L。

关键词： Students  

摘要： Background: Early exposure to Computer Science (CS) and Computational Thinking (CT) for all is critical to broaden participation and promote equity in the field. But how does the introduction of CS & CT into primary school curricula impact learning, perception, and gaps between groups of students? Methodology: We investigate a CS-curricular reform and teacher Professional Development (PD) program from an equity standpoint by applying hierarchical regression and structural equation modelling on student learning and perception data from three studies with respectively 1384, 2433 and 1644 grade 3-6 students (ages 7-11) and their 83, 142 and 95 teachers. Results: Regarding learning, exposure to CS instruction appears to contribute to closing the performance gap between low-achieving and high-achieving students, as well as pre-existing gender gaps. Despite a lack of direct influence of what was taught on student learning, there is no impact of teachers’ demographics or motivation on student learning, with teachers’ perception of the CS-PD positively influencing learning. Regarding perception, students perceive CS and its teaching tools (robotics, tablets) positively, and even more so when they perceive a role model close to them as doing CS. Nonetheless gender differences exist all around with boys perceiving CS more positively than girls despite access to CS education. However, access to CS-education affects boys and girls differently: larger gender gaps are closing (namely those related to robotics), while smaller gaps are increasing (namely those related to CS and tablets). Conclusion: This article highlights how a CS curricular reform impacts learning, perception, and equity and supports the importance of i) early introductions to CS for all, ii) preparing teachers to teach CS all the while removing the influence of teacher demographics and motivation on student outcomes, and iii) having developmentally appropriate activities that signal to all groups of students. ©

关键词： 大数据   信息时代   互联网技术   计算机科学  

摘要： 随着我国科技水平的不断提升,互联网技术被广泛应用在多个行业中,互联网技术的应用给人们生活及工作带来便利的同时,也暴露出一些信息安全方面的问题。因此,在日常生活中应用互联网技术时一定要利用好这把双刃剑。文章深入地分析了面向大数据信息时代计算机科学的具体应用情况。

关键词： Harmonic analysis   Hafnium   Symbols   Search problems   Measurement   Indexes   Computer science   Group closeness centrality   pruning   prioritization   approximation  

摘要： Given a graph and an integer k, the goal of group closeness maximization is to find, among all possible sets of k vertices (called seed sets), a set that has the highest group closeness centrality. Existing techniques for this NP-hard problem strive to quickly find a seed set with a high, but not necessarily the highest centrality. We propose PRESTO, a new solution that can efficiently provide both approximate and exact answers to the group closeness maximization problem. PRESTO continuously calculates the centrality of different seed sets until a time limit is reached or it identifies a seed set with the highest possible centrality. It prioritizes seed sets to quickly find ones that are highly central and thus can be used as accurate approximate answers to the problem. Furthermore, PRESTO can proactively discard large groups of seed sets that cannot have the highest centrality, thereby drastically speeding up the discovery of approximate and exact answers. In our evaluations, compared to other state-of-the-art solutions, PRESTO finds seed sets that have up to 39% higher centrality.

关键词： computer   simplicity   Turing  

摘要： *** We have defined the Conscious Turing Machine(CTM)for the purpose of investigating a theoretical computer science(TCS)approach to consciousness[1].For this,we have hewn to the TCS demand for simplicity and *** CTM is consequently and intentionally a simple *** is not a model of the brain,though its design has greatly benefited—and continues to benefit—from neuroscience and psychology.

关键词： 健康教育互动模式   子宫脱垂   盆底重建术   心理状态   生活质量  

摘要： 目的:探讨健康教育互动模式干预,对子宫脱垂盆底重建患者心理状态、生活质量的影响.方法:选取2020年1月至2022年1月本院收治的96例子宫脱垂患者作为研究对象.根据护理干预方案不同将其分为观察组(n=51,健康教育互动模式干预)与对照组(n=45,常规护理干预).比较两组患者干预前后心理状态和生活质量.结果:两组干预后抑郁自评量表(SDS)及焦虑自评量表(SAS)评分均较干预前下降,观察组SAS、SDS评分低于对照组,差异有统计学意义(P<0.05);两组干预后健康感觉、功能恢复、生活满足感、认知功能、心理状态评分均较干预前上升,且观察组上述评分高于对照组,差异有统计学意义(P<0.05).结论:健康教育互动模式干预可明显改善子宫脱垂患者心理状态和生活质量.